Mobile Health

Interview/Podcast: Tim Fowler Discusses Bluetooth®-Low-Energy Enabled iPhone M-Health App Pt.1

10 Mins read

tim fowler

tim fowler

During this year’s Mobile World Congress in Barcelona, Cambridge Consultants, a leading technology product design and development firm demonstrated their new Bluetooth low energy (BLE) Blood Pressure Profile iPhone app. Cambridge Consultants recently worked with CSR on tools and example device software that assists developers wishing to create applications for Apple’s latest iPhone and Mac products, specifically the growing mobile health (mHealth) market. The BLE iPhone app demonstrates the transfer of blood pressure readings using the BLE Blood Pressure Profile, while running on an example single-mode BLE device that could readily be incorporated into a blood pressure monitor. Faced with several challenges relating to power consumption, data transfer requirement and constraints of the smartphone. Cambridge Consultants is able to leverage its technical and medical regulatory expertise to optimize usability for both the device and the smartphone to meet the needs of the mHealth space.

For mHealth, both local and wide-area communications are required and with most mobile phone operating systems providing native Bluetooth stacks, BLE is an ideal technology for integration.  BLE technology is designed for low peak current consumption, permitting operation via standard coin-cell batteries and battery life of up to one year.


In the first part of this interview/podcast series, HIT Consultant speaks with Tim Fowler, Commercial Director, Wireless Division of Cambridge Consultants to learn more about:

  • Cambridge Consultants & Tim Fowler background/overview
  • Deep dive into Bluetooth low energy technology
  • BLE Blood Pressure Profile iPhone app

HIT Consultant: Can you provide a background/overview of yourself and Cambridge Consultants?

Tim Fowler: Sure, I don’t know how much you know about Cambridge Consultants in general, but we are a fee for service product and technology design company. My role is within our wireless division and I am a commercial director in the wireless division. And part of my role is to help drive sort of the market side of our business in particularly around technology to both help steer where we think there are interesting technical areas. I don’t do the technical work myself; we have a very able team of people who are much more technically competent than I am. Primarily everyone within the organization is an engineer, mathematician, or a scientist. I myself was an engineer for more than a decade before moving into marketing and product management type roles. Cambridge Consultants has 3 main focus areas, probably two thirds of our business comes from either med tech or wireless and the reason why we are engaged in sort of the connected health is because it is sort of the intersection between our two biggest areas of business, wireless communications and medtech effectively.

I have had a reasonable amount of my time has been spent working with both technologies and clients in the connected health I would say probably more than anything else in the connected health type of applications.

HIT Consultant: Recently, Cambridge Consultants presented a new Blood Pressure Profile application using Bluetooth low energy (BLE) for the iPhone at this year’s Mobile World Congress, can you tell me more?

Tim Fowler: So let me start by giving you some background context, we founded Cambridge Silicon Radio as a spinout. Cambridge Silicon Radio the market leader in Bluetooth and the Bluetooth standard you are pretty familiar with for doing things like your headset and your car kit and transferring pictures and a whole range of other things that Bluetooth is probably well known for. What it is probably less well known for is the fact that is has a whole range of profile to do other applications. In the last few years through organizations like Continua ordinary Bluetooth has been used for providing an open mechanism for transferring health information between a device, typically a medical device and a backend server through a communication network. There are quite a range of devices that are already starting to appear that use the standard Bluetooth technology for medical information and we were the first organization to be able to provide a toolkit of any type to be able to build that wireless connectivity into their medical products and we put it into things like weighing scales for a good example of other things. That said however, the energy consumption of standard Bluetooth is too high to work off small coin cells typically it works off larger batteries that can deliver higher peak currents. The difficulty with coin cells is that they are not able to deliver their energy very fast not able to deliver high peak currents. So it sort of using Bluetooth on its own was a shift in both in terms of how long the device could last based on the battery and what type of battery you could use it sort of limits how small the device you could put them into. Bluetooth low energy was a solution that sort of was created by members of the Bluetooth fig, several companies involved in it, but CSR and Nokia was two of the key drivers behind the idea of the technology which was to provide ability for simpler devices to have simpler communication. By simpler, I mean not looking to do streaming or something else the way you are trying send small amounts of data or provide small amounts of control.

Then, Bluetooth was much more geared up for creating connections between devices even if those connections were transient. Having a mechanism to create connections and send relatively large or even streamed information. But there are some applications where you only want to send relatively small amounts of information and you don’t need the ability to have a connection. You need some type of association between the two ends and you still need to maintain some type of security, but you don’t want the path consumption overhead of some of the things that Bluetooth had. So Bluetooth low Energy strand was defined which have the ability for devices to have a very rapid wake up communicate and go back to sleep, which means while they consume energy while their active, the vast majority of the time they are very inactive. So overall, the energy consumed from the battery is low and it is sort of a low overhead relative to the sorts of connection you need from voice it is a much lower overhead to set up the transfer. BLE have applications that range from providing connections from your watch to your phone so that you can set your watch for network time or put on your watch whose calling you on your phone all sorts of consumer style applications of that type through to transferring medical information from devices that currently the user doesn’t have the idea of recharging and the user probably never replacing the battery. They may well have a battery when they buy them but the probably throw them away when the battery runs out. Have a battery life of a year or two and then the device will pretty well be worn out, so the user doesn’t have to worry about charging it. Bluetooth low energy (BLE) enables you to put connectivity to those sorts of devices without changing that battery management ratio. It doesn’t consume so much power that you have go turn the device into something that needs a replacement battery and examples of that are things like glucose meters where people buy them and they are relatively low cost and they can buy them in the pharmacy. They can consume a large number of strips potentially, but when reading the strips the glucose meter is usually worn out around about the same time the battery has run out rather than have to re-charge everything else and What BLE does is allows me to put wireless connectivity to those sorts of devices without changing that battery experience.

The reason we did the work for Apple is because Apple is the first mainstream handset provider to incorporate Bluetooth low energy as standard into their handsets. So, it was introduced in the iPhone 4s. While I don’t have Apple’s direct statement on it, I believe Apple will put it in every product that they release after the iPhone 4s and actually it is also in the iMac Mini it’s in the new MacBook Air I believe and it’s also in the new iPad which came out today that been out a couple of weeks ago or least week it hits the stores today. Bluetooth Low Energy or Bluetooth 4.0 is in there as well. So, all of Apple ecosystem of products will be able to connect to these devices. There is obviously then two areas of interest for people, well can I change my device so that I can change my device so that fact it can talk to an iPhone or an iPad or any of the other mac or apple products. And what do I need to do to do that? So CSR contracted us to both fill the set of tools to help act in device manufacturers to make medical devices easier to work for them to work in the Apple ecosystem. So tools that run on a Mac tools that help them get the devices program with their applications. But in order to make it easy to integrate those, that connectivity into that product. While BLE defines some profiles that tell you how to it, what CSR wants to do its do almost all the work, do that framework,  and any bit that was missing from that framework be the how I get the senor data in case of being it a blood pressure meter. How does my blood pressure meter present its data? That can be programmed by the device manufacturer but everything else needs to do in terms of formatting the data and sending over their air making connections and finding the phone and paring all those things have already been done for them. So that is what are demonstrated device did. So we wrote code for the Bluetooth device for the blood pressure meter that does everything else except take your blood pressure. It doesn’t pump up a cuff or listen to your heartbeat. Other than that it does everything else you need to communicate the data. Having communicating the data we also wanted to show people how to integrated it into the phone and while the technology is in principal simple. In order to make it easy for the user to do all the things it needs there are some things To get those applications up to the phone and what does it mean when those applications you are running is in the background. How do you use those mechanisms to bring it to those users’ attention that the data been transferred? How do you make something happen when it wants to transfer the data? So again we applied our expertise in smartphone applications and particularly the use of these connectivity services in order to make a demonstration that showed how you could then build something that was suitable for the users. So it would show that you can find the device and connect to it straight forwardly and then when you receive data it would notify you in the standard mechanism, which is what the users would be expecting from apps on the iPhone. And obviously going forward I suspect that other smart phone platforms will want to follow where Apple has gone, I suspect Android will follow I suspect within a year. I don’t have any inside information of what Android is doing but I suspect within a year that Android will support Bluetooth 4 or BLE as it’s called. That will become probably the dominant way of transferring some medical information from the medical device to a smart phone or another source of product. So what we were showcasing was a sort of end to end solution that helps people get this solution into their devices and the example we used was a blood pressure meter

HIT Consultant: Now what are some of the average life battery life consumption metrics using BLE?

Tim Fowler: That is a very good question and I don’t actually know the actual technical parameters but from the number of studies we have done for technical clients it is suitable for long battery life devices running from coin cells so it does depend somewhat on the application as to how long the battery will last. But on something like a blood pressure meter where in the actual fact a blood pressure meter is not a good example, because blood pressure meter typically has a cuff and a pump and almost all of the energy in a blood pressure meter is consumed in driving the pump rather than anything else. But on any one of the number of medical devices our expectations that is very possible to get years of use out of coin cells adding Bluetooth low energy connectivity to them. That is really is considering that most of these health devices are used a few times a day rather than continually. There are some applications that looking to do continually monitoring so every few seconds or every few minutes and in those applications so battery life is likely to be reduced somewhat, but still probably longer than the life expectancy of application that are putting them in. So generally for most applications for people that are trying to use BLE the battery life of the connectivity is longer than the expected use life of the device

HIT Consultant: Tell me more about the basic data transfer and size constraints using BLE and how that ties into the security aspects of sharing patient data across from one mobile device to another and communicating it to the hospital network?

Tim Fowler: So the security sits at two levels one is at a local link between the device and the medical device and the cell phone and there is a user involved security mechanism in the user needs to associate his medical device with his phone and the communication at that point becomes private so it is secured. If you need to know exact technical details, I would need to get someone who is much more familiar with the protocols, but suffice to say it’s a standard feature of Bluetooth but it is a secure mechanism for effectively replacing a cable between two devices. So rather plugging a cable in either end it has a mechanism of  associating the two devices instead and once associated data can be securing passed between the two ends.

So there are two parts, one is the pairing process is a key exchange then the link is secured with a shared key. Once you get the data on the phone and that comes down to the definition of the application you are running. There are number of standard approaches for how you can send the data from the cell phone into a hospital server and the process we must be closely involved with is the standardization process driven by the continual line and the continual line has written specifications themselves but they are recommending a set of already used medical communications protocols for transferring information securely and reliable from a device like a cell phone something that can continual call a manager and the backend service that should be using protocols like HL7.

Stay tuned for part 2 coming soon…

About Tim Fowler: 

Tim has extensive technical and commercial experience within the wireless industry. He is a Commercial Director in Cambridge Consultants’ Wireless Division. He is responsible for market and business development of wireless projects within Cambridge Consultants. He runs all the firm’s broadband wireless activities. He has also had overall responsibility for program management for a number of large wireless development projects that have included technologies the short-range Ultra Wideband (UWB) technology to wide-area systems such as WiMAX, WCDMA and LTE. Tim also took responsibility for management of Cambridge Consultants Bluetooth business.

He has been a speaker at numerous conferences on the subject of broadband wireless technology evolution.


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